So many movies every year play it safe and avoid doing anything risky and unusual that I feel guilty coming down on “Penelope” for having a reach that exceeds its grasp. Still, if you’re going to walk the high wire without using a net, there are penalties for not reaching the other side.

How does “Penelope” go against the grain? For one thing, it starts with “Once upon a time...” — always risky territory for a movie that isn’t a cartoon. It extends the whole storybook notion by setting the film in an unnamed city that’s obviously London, yet having most of the principal cast — including the British James McAvoy and the South African–born Richard E. Grant — speak with American accents in an attempt to make it feel unmoored in place and time.

“Penelope” traffics in metaphor, so one can hardly blame the filmmakers for playing around with the storytelling. Christina Ricci plays rich, young Penelope, who’s born with a pig snout because of an old curse that dictated that the upper-crust family’s next daughter would be hideous until an aristocrat pledged to love her until death, no matter what she looked like. Penelope’s mother (the brilliant Catherine O’Hara, ill-used) keeps the girl locked away from the world and parades one to-the-manor-born suitor after another in front of her daughter, only to have the men make tracks when they see her porcine visage.

All of those men signed a non-disclosure agreement, but not silver-spoon simp Edward (Simon Woods). When he runs screaming to the police about the pig-monster woman he’s seen, he becomes a public laughingstock. So Edward and tabloid journalist Lemon (Peter Dinklage) set out to get a photo of the reclusive Penelope by drafting the posh but gambling-addicted Max (James McAvoy) to woo her in the hopes of getting her picture.

Penelope and Max fall for each other through a one-way mirror, but when he sees her and finds out about the curse, he refuses to marry her — for reasons that will become clear later, and which won’t be revealed here. But Penelope decides to run away and finally see the world outside her room, and in doing so, begins to accept herself and to finally make her own friends, including tough-talking courier Annie (Reese Witherspoon, whose Type A Productions backed the film).

The wide-eyed, fable-like vibe of the film occasionally works — art directors Ged Bryan and John Reid make Penelope’s first glimpse at life beyond the manor’s gate look like a vast cityscape, all stacked on top of itself — but this is the kind of oddball movie (like, say, “Willy Wonka and the Chocolate Factory” or “Delicatessen”) that has to work just perfectly or it collapses like a house of cards. And despite having a lot to recommend about it — Ricci and McAvoy make for a nifty couple — “Penelope” can’t quite maintain its balance. It’s not eccentric enough to be as otherworldly as it wants to be, but it’s too self-consciously quirky to perform on its own merits.

If nothing else, the younger female audience that will respond most to the love story and girl-empowerment plot will probably be most forgiving of its narrative flaws, so at least “Penelope” has that in its favor. Anyone not in that demographic, however, may not be so willing to forgive its shortcomings.